Friedman, Herbert A. (1916–2001)

American space scientist and astrophysicist who played an important role
in the development of X-ray astronomy. After earning a Ph.D. from Johns
Hopkins University (1940), he spent most of his career at the US Naval Research
Laboratory. He pioneered observations of the X-ray sky using rocket-borne
instruments. Although X-rays from the Sun
were first detected in 1948 by T. R. Burnright, they were studied systematically
from 1949 by Friedman and his colleagues, who observed X-ray activity throughout
a full solar cycle of 11 years. Friedman
also studied solar ultraviolet radiation and in 1960 produced the first
X-ray and ultraviolet photographs of the Sun. In 1965, his observations
of an occultation of the Crab
Nebula by the Moon proved that Tau X-1, the second X-ray source to be
detected beyond the Solar System, coincided with the Crab.